One known 3D display system that presents images viewable from various viewing points of multiple users is, for example, the Integral Photography (IP) 3D-image system developed by NHK (Japan Broadcasting Corporation).
FIG. 1 illustrates an example of the IP 3D-image system.
In the IP 3D-image system, a camera (video camera) 202 captures an image of an object through a lens array 201.
As shown in FIG. 2A in plan view and FIG. 2B in cross-sectional view, the lens array 201 has multiple microlenses disposed in a plane. The camera 202 captures the image of the object through each of the lenses.
In the IP 3D-image system, a display apparatus 203, such as a liquid crystal display, displays the image captured by the camera 202. A lens array 204 is disposed over the front face of a display screen of the display apparatus 203. The lens array 204 has the same structure as the lens array 201. A user sees the image displayed on the display apparatus 203 through the lens array 204. Thus, the user is able to view the image of the object of a certain viewing point.
This means that the image captured by the camera 202 is a combination of image elements (referred to as microlens image-elements hereinafter) of the object seen through the microlenses of the lens array 201. Thus, the image displayed on the display apparatus 203 is a combination of the microlens image-elements. The combination of the microlens image-elements is viewed from a certain viewing point through the lens array 204 having the same structure as the lens array 201. The image of the object seen from that viewing point is therefore formed of pixels which are formed of the microlens image-elements seen through the microlenses of the lens array 204.
Accordingly, the IP 3D-image system presents images that can be viewed from various viewing points of multiple users.
To briefly (or theoretically) describe the IP 3D-image system, an image of an object seen from a certain viewing point is formed of pixels that are formed by combining microlens image-elements of the microlenses of the lens array 204.
This means that the image resolution presented to a user depends on properties and density of the microlenses of the lens arrays 201 and 204. However, there are limits to reducing the size of the microlenses and also to the number of the microlenses, thus leading to difficulties in providing users with images having high resolution.
Another 3D display system that presents images viewable from various viewing points of multiple users is, for example, Zebra Imaging developed by Zebra Imaging, Inc.
Zebra Imaging uses holography technology to present high-resolution images that can be viewed from various viewing points of multiple users. However, because the images displayed using Zebra Imaging are holograms, the production of the images requires many hours for calculation, thus leading to difficulties in displaying moving images.